The Marvel Studios film starring Robert Downey Jr. debuted with a massive $174.1 million last weekend and has already sold more than $768 million of tickets worldwide. The movie should rake in an additional $70 million or more this weekend domestically, according to those who have seen audience survey data.

That would be more than enough to again claim No. 1, leaving "The Great Gatsby" to settle for the runner-up position. Baz Luhrmann's 3-D adaptation of F. Scott Fitzgerald's 1920s classic novel is poised to debut with a solid $45 million. (Warner Bros. is predicting a softer opening of around $35 million.) The film, whose high-profile cast is led by Leonardo DiCaprio and Carey Mulligan, will perform far better than "Peeples," the only other movie hitting theaters this weekend. The low-budget comedy produced by Tyler Perry may take in as little as $8 million.

Last August, Warner Bros. announced it would not release "Gatsby" as originally planned in December 2012 because Luhrmann needed more time to work on the film's 3-D effects and its soundtrack -- which was curated by Jay-Z and includes music from his wife Beyonce, Kanye West and will.i.am. The film, co-financed by Warner Bros. and Village Roadshow for about $100 million, follows a Midwesterner who arrives on New York's Long Island and becomes transfixed by the seemingly glamorous lifestyle of his neighbor, Jay Gatsby.

Beyond this weekend, "Gatsby" could get a boost because it will be the opening-night movie at the Cannes Film Festival next week. Typically, that slot at the star-studded festival is reserved for a world premiere, but "Gatsby" will have already been in U.S. and Canadian theaters for five days when it plays in Cannes on May 15. (The picture will debut in a handful of European markets next weekend.)

“I think [the Cannes premiere] will breathe a different kind of life into the domestic play,” Warner Bros. president of worldwide marketing Sue Kroll told The Times in March. “This is a film for the entire summer, not just for opening weekend or the weekend after.”

The film has not received overwhelmingly positive reviews. On Thursday morning, it had only notched a 39% "fresh" rating on Rotten Tomatoes.

Despite the mixed reviews, audience interest in the picture heading into the weekend remains strong. Fandango reported that as of 10 a.m. PDT Thursday, "Gatsby" represented 65% of the day's ticket sales. The film was "tracking to be one of our biggest non-franchise advance ticket-sellers," Fandango President Paul Yanover said.

So far, female moviegoers appear to be most interested in the movie, but it is also generating strong buzz among African American.

"Peeples," which features a predominantly black ensemble cast including Craig Robinson and Kerry Washington, is also tracking well with African Americans. The movie is only the second to ever be billed as "presented" by Tyler Perry, who produced the film. (He also "presented" 2009's Oscar-nominated "Precious.")

However, throwing Perry's name into the film's credits doesn't look like it'll have much of an impact on the picture's gross. In fact, the poorly reviewed movie could have the lowest debut ever for a film associated with the prolific writer-director-actor. Currently, that record goes to "Daddy's Little Girls," which launched with $11.2 million in 2007.

"Peeples" centers around a family reunion interrupted by the news of a couple's surprise engagement. Fortunately for Lionsgate, the studio didn't spend much to produce "Peeples," which had a budget of around $15 million.

Overseas, Paramount Pictures will open "Star Trek Into Darkness" in seven countries, including Britain, Australia and Mexico. The launch will be a bellwether for how well the J.J. Abrams film will fare internationally, where it needs to be a success to help recoup its $190 million production budget. The filmmaker's first "Star Trek" was not a hit abroad, collecting just 33% of its worldwide $385.7-million gross overseas, where big-budget franchises are typically more profitable for Hollywood.